A genetic brain booster?

摘要

Long-chain polyunsaturated fatty acids (LC-PUFAs) are essential for brain function. Although LC-PUFAs can be obtained from food, they are also synthesized from precursor molecules. Recent research has identified the enzymes-FADS1 and FADS2-that direct this synthesis, and interestingly, the genes that encode these proteins are positioned in a head-to-head orientation on chromosome 11. Therefore, it is possible that common regulatory mechanisms might be at play. In this issue, Ameur et al. take this idea further and show that two common haplotypes are associated with LC-PUFA biosynthesis. Strikingly, the haplotype associated with more efficient biosynthesis shows a signature of having undergone positive selection. Given the importance of LC-PUFAs for the brain, the authors postulate that this haplotype might have been beneficial for early humans in terms of promoting brain-size expansion, especially during periods in which fatty acids were scarce.